Search
Close this search box.
Notifications
Clear all

How to Write USERMAT Subroutine for Hyperelastic Model in ANSYS

5 Posts
2 Users
0 Likes
1,905 Views
Posts: 4
Topic starter
(@Shons2324)
New Member
Joined: 10 years ago

Hello,

I am trying to write a usermat subroutine for Fung type material[1] in ANSYS,the constitutive form follows:

With the Help Document of ANSYS, I can easily model the isotropic hyperelastic material with the subroutine userhyper.F.

However, for anisotropic hyperelastic material, this doesnt work.

From the reference[2], I find that this can be done by subroutine usermat.F. But I cannot find something useful about

modeling hyperelastic material with usermat.F from the Help Document.

I really hope someone can offer me an example,so I can learn to write my own code.

Any help will be greatly appreciated.

Reference:

[1] Holzapfel, G. A., Gasser, T. C., & Ogden, R. W. (2000). A New Constitutive Framework for Arterial Wall Mechanics and a Comparative Study of Material Models. Journal of Elasticity and the Physical Science of Solids, 61(1-3), 148. doi:10.1023/A:1010835316564

[2]Biomechanical Face Modeling: Control of Orofacial Gestures for Speech Production. (n.d.). Retrieved January 12, 2015, from [url] http://membres-timc.imag.fr/Yohan.Payan/PhD/PhD_Manuscript_Nazari_2011.pdf [/url]

4 Replies
Posts: 4
Topic starter
(@Shons2324)
New Member
Joined: 10 years ago

Hope someone reply the topic!

4 Replies
Posts: 11
(@sonnavown)
Active Member
Joined: 15 years ago

[QUOTE=Touch2014,12918]Hope someone reply the topic!

Perhaps the Technology Demonstration Guide, Chapter 40: Large-Deformation Neo-Hookean Analysis (via UserMat Subroutine) could be of help.

Reply
Posts: 4
Topic starter
(@Shons2324)
New Member
Joined: 10 years ago

[QUOTE=Jobie.Gerken,12920]Perhaps the Technology Demonstration Guide, Chapter 40: Large-Deformation Neo-Hookean Analysis (via UserMat Subroutine) could be of help.

Thank you very much,Jobie.Gerken!
I have found that the Technology Demonstration Guide from ANSYS 15.0 contain Chapter 40,
Now, I can learn to write my own code from this example!
Thanks again!

Reply
Posts: 4
Topic starter
(@Shons2324)
New Member
Joined: 10 years ago

[QUOTE=Jobie.Gerken,12920]Perhaps the Technology Demonstration Guide, Chapter 40: Large-Deformation Neo-Hookean Analysis (via UserMat Subroutine) could be of help.
With this guide, I wrote my usermat code, and it linked successfully.
And ansys can get convergence with Displacement load.
However, ansys cannot get convergence with pressure load. It shows that some element have highly distorted or sometimes that some elements turn inside out.
So I am quite confused now!
Does anybody have successed in convergence?

Reply
Share: